Method of treating outer covers for aircraft



Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

KARL H'URTTIIE, OF AKRON,OHIO, ASSIGNOR TO GOODYEAR-ZEPPELIN CORPORATION, OF AKRON, OHIO, A CORPORATION OF DELAWARE.

METHOD OF TREATING OUTER COVERS FOR AIRCRAFT.

Io Drawing.

My invention relates to outer covers for aircraft and it has for its primary object the provision ofa method of treating such covers in order to insure a smooth outer surface thereon.

Another object of the invention-is to provide a method of treating and applying covers to the hulls of rigid airships.

Heretofore, the practice of tautcning the outer covers of airships and airplanes involved the operation of manually drawing the fabric tightly over the construction to be covered and subsequently applying upon the outside surface of the cover several coatings of so-called dope which contracted the fabric in order to render it sufficiently taut for practical purposes, as well as to render it waterproof. In order to avoid excessive wind resistance upon the outer cover of an aircraft so treated, the protective coatings of dope ap lied thereto must have a smooth surface. uch smoothness could be provided by applying a large number of successive coatings of dope until the desired smoothness was obtained. This method involved the addition of excessive undesirable weight to the cover. Also, smoothness cou d be insured by applying fewer coatings of ope and by employing a special smoothing process before so the application of each successive coating. The dope, which sometimes was mixed with metallic powder of reflective quality, was applied manually with a brush or by spraying apparatus. There was no appreciable difference between the results obtained by these two methods of application.

While applyingthe first coatingof dopc.the solvents thereof were very rapidly absorbed by the fibers of the fabric, thus causing. by the 40 drying thereof, the solid ingredients of the dope to be deposited upon the outer surface. These depositions of the solvents produced a very rough outer surface. Before another coating was applied. the rough surface-was smoothed by sandpapering or other similar operation. Generally, after each application of a new coat of dope, the smoothing process was required to be repeated. This repeated operation was undesirable because it was likely to result in injury to the fabric, particularly at locations where the unevenness of the supporting structure caused the cover to bulge. This disadvan- Application filed August 29, 1927. Serial No. 216,331.

other water repelling substance; for example,

paraffin. aluminum oxide, etc. The outer side of the fabric is then prepared for a coating of dope by singeing or otherwise removing the fuzzes and naps therefrom.

The impregnation of the inner side of the fabric serves both as a protective means for the covering against moisture from the interior of the airship and as a filler to close the pores or interstices between the fibers of the material. This impregnation is effected either manually or mechanically, but not to such degree that the outer surface is changed from its originalcondition. It is necessary that the outer side remain in its original condition in order to provide a surface upon which the dope will adhere properly. The material for impregnating the fabric may be applied in the form of powder, liquid, solid or otherwise, and it shall be protective without altering in any wav the mechanical properties of the fabric. On the other hand. the dope on the outer surface of the cover serves to tauten the cover and to increase its strength.

After the impregnating material has been applied to the inner side of the cover, the latter is then positioned manually upon the supporting structure of the aircraft and the dope is subsequently applied. The fabric is so affected by the dope that it tends to contract and becomes taut throughout. The firstcoating of dope upon the outer surface of the cover after the latter has been positioned and tensioned does not penetrate through the interstices of the fabric. because they have been closed by the impregnating'material and absorption is thereby prevented. Because of this fact, the dope provides a very smooth surface without requiring a smoothing process before the application of another coat. The quantity of dope required is much less than that which would be required by, the practices heretofore known and by obviating the smoothing operation, such as sand-papering, much time and labor that otherwise would be necessary are dispensed with. v

Although I have described in detail onl one application of the invention, it will be apparent to those skilled in the art that it is not so limited but that various minor modifications may be made therein without departing from the spirit of my invention or from the scope of the appended claims.

What I claim is:

1. A method of treating covers for aircraft which comprises applying a moisture-repelling substance to the inside surface of the cover only, securin the cover under tension to the framework an airship and thereafter coating the outer surface of the cover with a protective contractive dope.

2. A method of treating fabric covering for aircraft which comprises applying a coating of moisture-repelling substance to the inside surface only of the cover while the outside surface remains in its original condition, securing the cover under tension to the hull structure of the airship and thereafter coating the outer surface of the cover with a plurality of coatings of protective dope serving to tauten the fabric.

3. A method of treating fabric covering for aircraft which comprises impregnating the inner side only of the fabric covering with a waterproof substance, securing the covering under tension upon the aircraft and thereafter smoothing and tautening the covering by applying to the outer side thereof a plurality of coatings of dope serving to contract the fabric about the aircraft.

4. A method of treating covers for aircraft which comprises applying a moisture-repelling substance to the inside surface of the cover only, removing the fuzzes and naps from the outside surface thereof, securing the cover under tension to the framework of an airshi and thereafter coating the outer surface ofthe cover with a protective contractiv'e e.

l n witness whereof, I have hereunto signed my name.

Signed at Akron, in the county of Summit, and State of Ohio, this 26th day of August,

KARL HURTTLE. 

